1. Field of the Invention
The present invention relates to a light emitting device and a method of packaging the same. More particularly, the present invention relates to an electron emission device and a method of packaging the same.
2. Description of Related Art
Currently, light emitting devices applied in existing mass-produced include gas discharge light sources and field emission light sources. The gas discharge light source may be applied to a plasma panel or a gas discharge lamp, wherein gas that filled in a discharge chamber is dissociated under the effect of an electric field between a cathode and an anode, and due to gas conduction, transition occurs and ultra violet (UV) light is emitted when electrons collide with gas, and phosphor in the same discharge chamber absorbs UV light to emit visible light. The field emission light source may be applied to a carbon nanotube field emission display etc., wherein an ultra high vacuum environment is provided, and an electron emitter of nano carbon material on the cathode is produced for helping electrons to overcome the work function of the cathode to escape from the cathode due to the high aspect-ratio microstructure of the electron emitter. In addition, a phosphor layer is disposed on the anode made of indium tin oxide (ITO), and electrons escape from carbon nanotube of the cathode under the effect of high electric field between the cathode and the anode. Thus, electrons may react with the phosphor layer on the anode in the vacuum environment to emit visible light.
However, there are disadvantages in both aforementioned light emitting devices. For example, considering the attenuation after UV irradiation, the material selection for gas discharge light source should meet a special requirement. Moreover, the light emitting mechanism of gas discharge requires two processes to emit a visible light, thus, the energy loss is considerable, and it will cost more if plasma needs to be generated during the process. In another aspect, electron emitter has to be evenly grown or disposed on the cathode of the field emission light source, however, the technology of mass-producing of such cathode structure is still immature, and the problems of poor electron emitter uniformity and poor production yield are still not resolved. Moreover, the space between the cathode and the anode of field emission light source requires precise control, and ultra high vacuum packaging is difficult to process, so the cost of production increases accordingly.
In addition, it is important for thinning the light emitting devices and improving the light emitting uniformity when designing a new light emitting device.